A wide variety of liquids are used for heating and cooling purposes. However, the successful use of liquids for such purposes generally requires that the heating or cooling capacity of the liquid be withdrawn by means of a heat exchanger through which the liquid flows in indirect heat exchange with another liquid or a gas.
Many different types of heat exchangers are available but, in general, they are designed for use with relatively pure liquids so that fouling of the heat exchanger, regardless of whether it is the shell or tube side, or both sides, is minimal. Additionally, the heat exchangers are mostly useful for low pressure operation, i.e. below 200 psi, although there are some which are suitable for high pressure use but they are not designed for use with fouling liquids.
One of the uses of heat exchangers for cooling purposes is in deep mines where temperatures of 120.degree. to 140.degree. F. are not uncommon. An efficient way to cool deep mines is to produce an ice slurry at ground level and then feed it through a high pressure heat exchanger located deep in the mine. The resulting warm aqueous liquid is returned to ground level and again cooled to an ice slurry which is then recycled into the mine heat exchanger.
A mine cooling system as described requires a high pressure heat exchanger because the pressures involved are often above 3000 psi. Additionally, the system should be one which can handle an ice slurry without being easily plugged by ice deposits and should also be useful for cooling a wide range of waters available in a mine, many of which have a high mineral content which could foul the system. For example, several years ago mines tried closed loop high pressure shell and tube heat exchangers to directly cool the dirty mine water but they quickly fouled and had to be scrapped.